Electron discharge device



Patented Sept. 20, 1938 UNITED STATES PATENT OFFICE 7 Claims.

The present invention relates to electron discharge devices and more particularly to a novel construction of vapor electric tube primarily adapted for the generation or by-passing of appreciable amounts of electric current of either an alternating or pulsating nature, when properly excited by direct or alternating current from any suitable external source, as shown in my copending application, issued on June 22,.l37, as

Patent No. 2,084,478. l

One of the objects of the present invention is to provide a novel construction ofrvapor electric tube employing a readily ionizable atmosphere, in combination with a common electron emitting means, a plurality of associated -grids and anodes and means for permitting a free but controlled flow of electrons from substantially the entire surface of the emitting means.

Another object of -the present invention is to provide in a vapor electric tube having multiple grid and anode elements, a common cathode or electron emitting means so constructed and arranged as to permit a free and complete flow -of electrons from substantially its entire emitting surface to one plate at' a time.

A further object of my invention is to provide a method of transferring energy in a vapor electric tube having a plurality of grids and cooperating plates and common electron emitting means, by directing and controlling the emission from substantially the entire surface of the common electron emitting means to one plate at a time.

The above features, advantages and capabilities of my present invention will become apparent from a description of the accompanying drawing in which I have illustrated one form of my invention but the form there shown is to be understood as illustrative only and not as defining the limits of my invention except as expressed or intended to be expressed in the appended claims.

Fig. 1 is a view partially in section of an electron discharge device illustrating an embodiment of my invention.

Referring to the drawing in detail thereis disclosed an evacuated bulb I in which is mounted a common cathode or electron emitting means provided with leads 3 and 4 for supplying heater excitation. This common cathode may .be heated either indirectly or as a filament. Surrounding or encompassing the electron emitting means are provided multiple grids 5 and 5 having heat radiators I and 8 connected to lead wires 9 and I0, respectively.

Surrounding these grids are (Cl. Z50-27.5)

plates or anodes II and I2 connected to lead wires I3 and I4, respectively. The grld heat radiators I and 8 are employed to maintain the grids cool and to reduce the grid emission.

There is provided a non-conducting partition 5 I5 having an outer diameter greater than that of the plates. This partition has a central opening which forms a close iit or contact with the outer surface of the common cathode. l

. In the form shown the partition is providedy l0 with a metal core I6 positioned between layers Il of suitable non-conducting material. 4This core is preferably biased through the connection I8 for the purpose ofrelieving it from a charge that may be built up therein. 15

The grids 5 and 6 aswell as plates or anodes II and I2 abut against this non-conducting partition which acts as a screen or baffle to prevent stray arcs between the adjacent tube sections. It also serves to center and anchor the multiple zo grids and plates.

The common cathode or electron emitting means may be ofthe oxide coated type, of caesiated metal, or of any other'type suitable for use with alkali metal vapors. In the disclosed em- 25 bodiment it comprisesv a tube-like sleeve I9 extending through the partition enclosing a heating coil 20. This sleeve is provided on each side of the partition with a plurality ofA openings 2l. By this'arrangement the free flow of electrons 30 from substantially the entire surface of the cathode or electron emitting means is permitted to one plate at a time when the tube is in operation notwithstanding the partition tightly lits around the cathode at such times as the grids 35 prevent simultaneous emission to the plates. In other words, stated in simple verbiage, in this type of tube with the cathode arranged as described, When in operation it acts as a sort of valve to direct and control emission from sub- 40 stantially the entire surface of the common electron emitting means to one plate at a time thus greatly increasing the eiciency of the tube..

The number of openings in the sleeve I9 and size thereof may vary. It is important, however, 45 that the displacement of the openings in the aggregate be sufficient to by-pass the iiow of electrons and ions from one portion of the electron emitting means to the other when the tube is in operation and at such times as the grids prevent 50 simultaneous emission to the plates.

The particular form disclosed has been employed with very satisfactory results in oscillating circuits to generate electron current from applied direct current source. This type of tube is 55 particularly important in low voltage oscillating circuits such as are necessarily employed in operating radio sets in automobiles.

In order toheat the cathode quickly to start the tube oscillating in the shortest possible time I preferably decrease the thickness of the cathode wall at and near its midsection since in a tube of this type a. heater coil tends to more quickly heat at its central portion. Thus by thinning the central or midsection of the cathode sleeve, as clearly shown in the drawing, at and adjacent this central portion of the heater coil, the cathode reaches an emitting temperature at that point far more quickly than other portions thereof. Thus the invention comprehends greater initial heat at the central portion with the subsequent uniform heat throughout substantially the extent of the cathode. It is, of course, to be understood that suilcient radiation is provided adjacent this point that no harmful overheating of the cathode takes place. 'I'his type of cathode is most effective when used with a noble gas filling such as neon, argon, krypton, xenon, or the like.

Having thus disclosed the invention, I claim:

1. In a vapor electric tube having ionizable atmosphere, a plurality of grids and cooperating plates, and common electron emitting means enclosed by the grids and plates and provided with suitable openings in its outer surface and so arranged and combined as to direct emission from substantially its entire emitting surface to one plate at a time for the purpose set forth.

2. In a vapor electric tube adapted for low voltage oscillating circuits for operating automobile radio sets, comprising a plurality of grids and cooperating plates, an electron emitting device common to both plates and grids, said emitting device being provided with openings in its outer surface so as to alternately afford when in 0peration emissionv from substantially its entire emitting surface to one plate at a time and to minimize the drop in voltage between the plates and emitting device.

3. In a vapor electric tube having ionizable atmosphere, a plurality of grids and cooperating plates, a non-conducting partition intermediate said grids, a common cathode passing through and fitting tightly into said partition, said cathode being provided with openings for by-passing the iiow of electrons and ions from one portion from substantially its entire of the cathode to the other and for directing and controlling emission from substantially the entire surface of the common cathode to one plate at a time.

4. In a vapor electric tube for low voltage oscillating circuits for operating automobile radio sets, a plurality of grids and cooperating plates. a non-conducting partition intermediate said grids, a common cathode passing through and fitting tightly into said partition, said cathode being provided with openings for by-passing the flow of electrons and ions from one portion of the cathode to the other and for directing and controlling emission from substantially the entire surface of the common cathode to one plate at a time.

5. In a vapor electric tube, a cathode therefor comprising a sleeve-like member having its midsection of less wall thickness than the remainder to permit more rapid initial heating and emission at that portion with sufilcient heat radiation from the surfaces of the cathode adjacent the mid-section to prevent such surfaces from rising to a higher final temperature than other portions of the cathode.

6. In a vapor electric tube having ionizable atmosphere, a plurality of grids and cooperating plates, a metallic partition intermediate said grids, a common electron emitting device passing through and fitting tightly into said partition. and means for insulating said partition from the grids and plates, said emitting device being provided withopenings in its outer surface so as to alternately afford when in operation emission emitting surface minimize the drop plates and emitting deto one plate at a time and to in voltage between the' vice.

7. In a vapor electric tube having ionizable atmosphere, a plurality of grids and cooperating plates, an insulating partition intermediate said grids and provided with a metal core, a common electron emitting device passing through said partition and in contact therewith, and openingsprovided in said emitting device for by-passing the flow of electrons and ions from one portion of the cathode to the other and for directing and. controlling emission from substantially the entire surface of the common cathode to one plate at a time.

RICHARD U. CLARK. 

